<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <div style="width: 500px;border: 1px solid red;">
        <div style="width: 20%;background-color: aqua;float: left">f</div>
        <div style="width: 30%;background-color: beige;float: right">a</div>
        <div style="width: 30%;background-color: beige;float: right">a</div>
        <div style="clear: both;"></div>
    </div>
</body>
</html>